The Lab Notes

The main theme of our research is to understand how gene regulation and genome organization tie in with each other. The Lab Notes are the latest headlines from the lab, featuring a collection of random thoughts and useful code snippets.

On bad statistical pratice

I have just published in GigaScience a short note entitled The signed Kolmogorov-Smirnov test: why it should not be used. I had discussed this issue previously on The Grand Locus, and I have refined the arguments through the publication process.

The “signed Kolmogorov-Smirnov test” is a non standard statistical practice on the rise in the field of genomics. This is unfortunate, as there are several reasons why this test should be avoided. First and most importantly, is that it does not test whether two samples have the same mean. Second, it is less powerful than the standard t-test.

Why is it used at all then? It is tempting to speculate that the reason may have something to do with p-hacking, which is the practice of changing statistical test until you find one that gives the p-value you expect. This of course has to be discouraged, and one way to do this is to highlight poor statistical practice. So my aim with this paper was to give a peer-reviewed reference that can be cited in order to argue against the use of this practice.

The editor of GigaScience and the reviewers have been...